How is the era of expansionist imperialism reflected in In D.W. Griffith's The Birth of a Nation?

I don't think that Griffith's film is overtly political in the sense of directly advocating expansionist imperialism. Yet, I believe that its statement about America, as a whole, fits into the expansionist imperialism narrative. The belief in American exceptionalism was a major part of the imperialist ideology that dominated American political interests at the turn of the century and into the early part of the 20th Century. The idea of America being a "chosen" nation was something that enabled it to spread its influence across the world without much in way of internally reflective opposition. Griffith's film does fit the idea in how it constructs American History. It does not acknowledge the Civil War or even Southern slavery as part of a narrative that is flawed. Rather, it makes the argument that America is an exceptionalist nation, incapable of an error in judgment. The laudatory tones of the film towards the "Old South" are representative of this. There is no internally reflective opposition or critique of slavery. Even the Civil War and the difficulty of life after it, the film lauds the attempts of the Klan as a force of law and order in a time of lawlessness, helping to enshrine the idea that no matter what, America stands for order and stability in a world that might be devoid of it. The ending of the film, one in which the power of a redemptive force becomes a part of how the nation is to progress, helps to feed the idea that America is a "chosen" nation, almost by divine prowess. These ideas within the film are elements that coincide with the expansionist imperialism in which America pursued vigorously at the commencement of the 20th Century.